Online PHP editor | refs for fekWt

<?php $a = 'a'; $b = '3'; $x = []; $contains_key = /** * @param array<string, string> $arr * @param string $key */ function(array $arr, string $key): bool { foreach($arr as $k => $_v) { if ($k === $key) { return true; } } return false; }; var_dump($contains_key($x, $a)); $x[$a] = 'yes'; var_dump($contains_key($x, $a)); var_dump($contains_key($x, $b)); $x[$b] = 'yes'; var_dump($contains_key($x, $b));